TSIO360MB Oil Breather Issue

[dlmorris]

Here's a new one for you K Model Gurus. Oil spray on belly from oil breather or air/separator even when oil level is below 6 quarts. No other indicators of trouble exist. I assume the cause is high crank case pressure. Question is why. Anyone had this issue.

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[Mike A]

Attached is the TCM SB concerning acceptable pressures and how to check them.

 

My K always spits a fine layer of oil out the breather.  I have not followed this SB and checked my pressures out.  I have replaced 2 jugs in the past 2 years and it has improved the issue considerably.  

TCM Service Bulliten M89-9 - Excessive Crankcase Pressures.pdf

[anthonydesmet]

Yep, same here, always out of the tube on the belly post flight and never any on the hanger floor. but no issues with engine as evidenced by my last two analysis or engine inspection at annual. My MB likes 6.5 quarts, anything higher and there is always a little more, anything less than 6 and still a little. It may look like a lot but I add 1qt about 15 to 18 hours so no real actual loss. My mooney mech says kind of normal for the continental.

[N33GG]

When those K models get older, they suffer from enlarged prostates and can't make it between oil changes.  That's all it is.

[dlmorris]

Thanks bunches guys for the knowledge base (especially you Mike for TCM-SB).

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[carusoam]

Along with the prostrate issues...

Worn/broken cylinders/rings can lead to increased exhaust bypass into the engine block.

TC'd engines have an increased ability to wear the cylinders/rings.

High exhaust bypass is often detected by the color of the oil. It gets dark quickly. The bypass can pressurize the block. Since it is vented, the gasses may escape, taking additional oil with it, out the vent..

How many hours since the top was OH'd?

Is your oil dark?

I am not a mechanic. I am only a PP...

Best regards,

-a-

[Guest]

Continental engines are famous for crappy cylinder life, turbocharged one are even worse. Typically by half life the choke is gone from the cylinder and they start to have higher blow by, black oil and venting oil issues.

Static cylinder compression readings can be misleading, following the S/B should give you some ideas. Interestingly Lycoming does not have a similar S/B.

Clarence

[DonMuncy]

My opinion is that Continental cylinders got a bad rap. I think MANY of them have been changed unnecessarily. Perhaps they don't last as well as they should, but not near as many are bad as are changed/overhauled.

[jackn]

I have been told a lot of things about Turbo Continentals by a lot of a&ps that weren't true. My real life eperience with new factory cylinders is the engine holds 8 quarts, uses about 1 quart in 20 hours. Upon shutdown, you will see the oil level about 1/3 quart lower, that will all come back. The oil should not turn black in 30 hours. That is a sign that the engine was run too hot for too long. You will see a couple of drops of oil on your drip pan in the hanger. That is normal condensation.

I have 250 hours on cylinders, but a friend who flies a 231 -LB went to TBO with not much change.

[mmgreve]

Similar issue here....

 

Our 231 has developed a bad habit of transferring the oil from he sump where it is most useful, to the underside of the plane where it is much less desired. The oil "consumption" is 0.5-1 quart per hours, so apart from the inconvenience it also limit the operation range significantly.

The oil on the belly is yellow and sticky, so clearly new and "unused" oil and we are sure that he oil is not being burned in the engine.

While our mechanic believe the oil to be leaking into the exhaust from the turbo, I highly doubt that, partly because the silencer (Liese) is clean and dry, and partly because oil leaks onto the nose gear door after landing. There are a couple of hoses the oil could come from, but I am wondering if it has to do with the oil separator that is installed?

[Retz]

I'm having a similar issue. 1/4 qt of oil per hour out the breather. Clean oil so not burnt from ring blow by. What's the first step to diagnose?

Did the MBs come with an oil separator?

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[carusoam]

What level did you fill it to?

What level does it fall to on the second hour?

Sure it's coming out the breather?

Couple of questions that come to mind....

Best regards,

-a-

[Retz]

Great questions.

I usually fill to 7.5. It is hard to say on first hour because of the durations of flights recently. The plane has a fresh oil change. It was happening pre oil change recently, it is just all my flights were shorter in duration, so wasn't as bad. Average appears to be 1/4 qt per hour. I'm positive it is coming from the breather because the extreme cleanliness of everything else around the breather and the oil dripping directly from inside the breather post flight.

Here are my last flights since oil change in order:

1. 4 hrs, start 8 qt, finish 6.5 qt

2. 3.8 hrs, start 7 qt, finish 6.5 qt

3. 2 hrs, start 7qt, finish 6.5

4. 4 hrs, start 7.5, finish 7.25

5. 3.4 hrs, star 7.25, haven't checked finish yet but still visible oil on belly

At the end of every flight I had visible oil on the belly of the aircraft. The oil is still fresh and clean even though it has been 17.5 hrs since oil change. Oil is AS 15w50 with camguard

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[Andy95W]

Maybe it's because of the Camguard.

[Retz]

Last flight it spit .75 qt in 3 hrs. ARGGGHH I'm not liking this.

I read the SB, is there some other way to check the crank case pressure other than an airspeed indicator? I don't have any of those lying around.

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[DonMuncy]

You presumably have one in your plane. You can use that one by plumbing onto your pitot tube. But you have to take proper precautions to make sure you don't blow it past VNE and you filter it enough to not blow crankcase vapor into it.

[ArtVandelay]

Last flight it spit .75 qt in 3 hrs. ARGGGHH I'm not liking this.

I read the SB, is there some other way to check the crank case pressure other than an airspeed indicator? I don't have any of those lying around.

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It looks like you are trying to keep it above 7 quarts, the higher the fuel level more it spits is out.  What happens when you start at 6.5 or less, does the rate start to drop?

[Retz]

So what is the safe level to run an MB? I was thinking that 6 min - 8 max, is there any risk or issues with running 6 to 6.5?

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[Andy95W]

Your engine sure seems to like 6.5-7 quarts. Make sure you give your engine a good day or two to fully drain down into the crankcase.

Minimum safe level? Keeping the oil cool enough is the driving factor.

[Guest]

Last flight it spit .75 qt in 3 hrs. ARGGGHH I'm not liking this.

I read the SB, is there some other way to check the crank case pressure other than an airspeed indicator? I don't have any of those lying around.

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You don't need to use an airspeed indicator, you can do it with a water manometer which you can build yourself. You'll need some clear tubing, water with a bit of food colouring, a tape measure for a scale and a board to fasten it to. The SB should provide the limits in inches of water as well as MPH.

Clarence

[ArtVandelay]

So what is the safe level to run an MB? I was thinking that 6 min - 8 max, is there any risk or issues with running 6 to 6.5?

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I believe aircraft engines are certified to run at 50% of capacity, I wouldn't go that low, Mike Busch recommends 2/3, I used 3/4, or for 8 max, start with 6, if 12, I'd start with 8. If going on a long trip (3+ hrs), then I start with 6.5.

[jackn]

Two things come to mind;

1. the case is getting pressurized from some source

 or

2. the output of the breather tube is getting negative pressure, thereby sucking out oil.

 

As an aside, most turbo drivers I know use either Phillips X/C or straight weight mineral oil. Synthetics and semi-synthetics are just too slick. Next oil change you may want to try this and see if anything changes.